I have heard of pregnancy glows and post sex glow and bacon glow, but I have yet to ever hear of engagement glow, especially when no one is sure there is an engagement. Since US Weekly invested a cover into telling all of us that Justin Timberlake and Jessica Biel are engaged they are going to pound that into my head and your head and every head they can and find any possible way to put it into an article just so they look good.
Seriously? And they can tell this from a photo because that is all they were looking at. They wrote the article just so they could use that sentence. The only other sentence in the article is describing what she is wearing which is presumably to describe to you, the reader, who may have some type of problem seeing photos despite being able to read the article what exactly Jessica is wearing in the photo.